duete; see due, ty 2 ]. syn: duty, obligation refer to something a person feels bound to do. A duty often applies to what a person performs in fulfillment of the permanent dictates of conscience, piety, right, or law: one's duty to tell the truth; a parent's duty to raise children properly.
Mutations in the RB1 gene are responsible for most cases of retinoblastoma. RB1 is a tumor suppressor gene, which means that it normally regulates cell growth and keeps cells from dividing too rapidly or in an uncontrolled way.
Most retinoblastoma occurring in only one eye is not hereditary; when the disease occurs in both eyes it is always hereditary. However, while less common, retinoblastoma may occur in only one eye and may still be hereditary and passed on to children, or inherited in siblings.ost retinoblastoma occurring in only one eye is not hereditary; when the disease occurs in both eyes it is always hereditary. However, while less common, retinoblastoma may occur in only one eye and may still be hereditary and passed on to children, or inherited in siblings.